Why do leaves turn yellow on hibiscus plants? Also, have black spots like a mildew. I pick off three/four every day. Plants are in containers, plenty of sun and bloom beautifully. Help appreciated. Live in Texas where it's hot-hot but already turning yellow even in spring.
Certified GKH Gardening Expert
It sounds like it may be aphids or scale, but could be several other pests as well. Fortunately, all the pests it could be are treated the same. Treat the plant with neem oil to get rid of them. Here is more information on neem oil: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm